C#读取系统文件信息(一）——调API读取文件类型

需求：

    做类似资源管理器的一个系统，现已读出各盘文件信息，需要我读出文件的类型以及图标。

思路：

    因为之前没有做过类似的功能，所以自己当时想的是：通过扩展名来判断是什么文件，直接给它返回（自己写）相应的文件类型。但最终舍弃了。因为这样的话需要列举的文件类型太多太多。并且查资料，大家显示的文件类型都是和本地资源管理器中的类型一一对应。所以肯定不是我想象的这样。

    所以继续查，找到一个调用windows API的一个方法，可以读取系统文件的信息，包括文件类型，包括Icon图标。

    下面是我整理的一个工具类：其中调用的是shell32.dll Windows API

   

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Runtime.InteropServices;
using System.Drawing;
using Microsoft.Win32;
/*
*文件名:获取文件信息公共类
*作者：赵寒
*创建时间：2016-6-20 17:15:13
*变更记录：始建
*/
namespace CommonUtils.Files {
public class FileIconUtil {
//在shell32.dll导入函数SHGetFileInfo
[DllImport("shell32.dll", EntryPoint = "SHGetFileInfo")]

public static extern int GetFileInfo(string pszPath, int dwFileAttributes, ref FileInfomation psfi, int cbFileInfo, int uFlags);

[DllImport("shell32.dll")]
private static extern int ExtractIconEx(string lpszFile, int niconIndex, IntPtr[] phiconLarge, IntPtr[] phiconSmall, int nIcons);

//定义SHFILEINFO结构
[StructLayout(LayoutKind.Sequential)]
public struct FileInfomation {
public IntPtr hIcon;
public int iIcon;
public int dwAttributes;

[MarshalAs(UnmanagedType.ByValTStr, SizeConst = 260)]
public string szDisplayName;

[MarshalAs(UnmanagedType.ByValTStr, SizeConst = 80)]
public string szTypeName;
}

[DllImport("Shell32.dll", EntryPoint = "SHGetFileInfo", SetLastError = true, CharSet = CharSet.Auto)]
public static extern IntPtr SHGetFileInfo(string pszPath, uint dwFileAttributes, ref FileInfomation psfi, uint cbFileInfo, uint uFlags);

[DllImport("User32.dll", EntryPoint = "DestroyIcon")]
public static extern int DestroyIcon(IntPtr hIcon);

//定义文件属性标识
public enum FileAttributeFlags : int {
FILE_ATTRIBUTE_READONLY = 0x00000001,
FILE_ATTRIBUTE_HIDDEN = 0x00000002,
FILE_ATTRIBUTE_SYSTEM = 0x00000004,
FILE_ATTRIBUTE_DIRECTORY = 0x00000010,
FILE_ATTRIBUTE_ARCHIVE = 0x00000020,
FILE_ATTRIBUTE_DEVICE = 0x00000040,
FILE_ATTRIBUTE_NORMAL = 0x00000080,
FILE_ATTRIBUTE_TEMPORARY = 0x00000100,
FILE_ATTRIBUTE_SPARSE_FILE = 0x00000200,
FILE_ATTRIBUTE_REPARSE_POINT = 0x00000400,
FILE_ATTRIBUTE_COMPRESSED = 0x00000800,
FILE_ATTRIBUTE_OFFLINE = 0x00001000,
FILE_ATTRIBUTE_NOT_CONTENT_INDEXED = 0x00002000,
FILE_ATTRIBUTE_ENCRYPTED = 0x00004000
}

//定义获取资源标识
public enum FileInfoFlags : uint {
SHGFI_ICON = 0x000000100, // get icon
SHGFI_DISPLAYNAME = 0x000000200, // get display name
SHGFI_TYPENAME = 0x000000400, // get type name
SHGFI_ATTRIBUTES = 0x000000800, // get attributes
SHGFI_ICONLOCATION = 0x000001000, // get icon location
SHGFI_EXETYPE = 0x000002000, // return exe type
SHGFI_SYSICONINDEX = 0x000004000, // get system icon index
SHGFI_LINKOVERLAY = 0x000008000, // put a link overlay on icon
SHGFI_SELECTED = 0x000010000, // show icon in selected state
SHGFI_ATTR_SPECIFIED = 0x000020000, // get only specified attributes
SHGFI_LARGEICON = 0x000000000, // get large icon
SHGFI_SMALLICON = 0x000000001, // get small icon
SHGFI_OPENICON = 0x000000002, // get open icon
SHGFI_SHELLICONSIZE = 0x000000004, // get shell size icon
SHGFI_PIDL = 0x000000008, // pszPath is a pidl
SHGFI_USEFILEATTRIBUTES = 0x000000010, // use passed dwFileAttribute
SHGFI_ADDOVERLAYS = 0x000000020, // apply the appropriate overlays
SHGFI_OVERLAYINDEX = 0x000000040 // Get the index of the overlay
}

//获取文件类型-赵寒-2016-6-20
public string GetTypeName(string fileName) {
FileInfomation fileInfo = new FileInfomation();  //初始化FileInfomation结构
//调用GetFileInfo函数，最后一个参数说明获取的是文件类型(SHGFI_TYPENAME)
int res = GetFileInfo(fileName, (int)FileAttributeFlags.FILE_ATTRIBUTE_NORMAL, ref fileInfo, Marshal.SizeOf(fileInfo), (int)FileInfoFlags.SHGFI_TYPENAME);
return fileInfo.szTypeName;
}

/// <summary>
/// 获取文件类型的关联图标
/// </summary>
/// <param name="fileExt">文件类型的扩展名或文件的绝对路径</param>
/// <param name="isLargeIcon">是否返回大图标</param>
/// <returns>获取到的图标</returns>
public Icon GetIcon(string fileExt, bool isLargeIcon) {
FileInfomation shfi = new FileInfomation();
IntPtr hI;
if (isLargeIcon) {
hI = SHGetFileInfo(fileExt, 0, ref shfi, (uint)Marshal.SizeOf(shfi), (uint)FileInfoFlags.SHGFI_ICON | (uint)FileInfoFlags.SHGFI_USEFILEATTRIBUTES | (uint)FileInfoFlags.SHGFI_LARGEICON);
}
else {
hI = SHGetFileInfo(fileExt, 0, ref shfi, (uint)Marshal.SizeOf(shfi), (uint)FileInfoFlags.SHGFI_ICON | (uint)FileInfoFlags.SHGFI_USEFILEATTRIBUTES | (uint)FileInfoFlags.SHGFI_SMALLICON);
}
Icon icon = Icon.FromHandle(shfi.hIcon).Clone() as Icon;
DestroyIcon(shfi.hIcon); //释放资源
return icon;
}

/// <summary>
/// 获取文件夹图标
/// </summary>
/// <returns>图标</returns>
public Icon GetDirectoryIcon(bool isLargeIcon) {
FileInfomation _FileInfomation = new FileInfomation();
IntPtr _IconIntPtr;
if (isLargeIcon) {
_IconIntPtr = SHGetFileInfo(@"", 0, ref _FileInfomation, (uint)Marshal.SizeOf(_FileInfomation), ((uint)FileInfoFlags.SHGFI_ICON | (uint)FileInfoFlags.SHGFI_LARGEICON));
}
else {
_IconIntPtr = SHGetFileInfo(@"", 0, ref _FileInfomation, (uint)Marshal.SizeOf(_FileInfomation), ((uint)FileInfoFlags.SHGFI_ICON | (uint)FileInfoFlags.SHGFI_SMALLICON));
}
if (_IconIntPtr.Equals(IntPtr.Zero))
return null;
Icon _Icon = System.Drawing.Icon.FromHandle(_FileInfomation.hIcon);
return _Icon;
}

}
}

    以读取文件类型为例，看如何使用这个工具类：

    读取文件类型分两类：文件夹与非文件夹

FileIconUtil _fileIconUtil = new FileIconUtil();

/// <summary>
/// 查询子目录及文件-赵寒-2016-6-20
/// </summary>
/// <param name="fileInfo"></param>
/// <param name="isAllFiles"> false 只查子目录，true子目录和文件</param>
/// <returns></returns>
public List<FileInfoEx> GetChildrenFiles(FileInfoEx fileInfo,bool isAllFiles=false) {
List<FileInfoEx> files;
DirectoryInfo parentDir;
FileInfoEx f;
files = new List<FileInfoEx>();
try {
parentDir = new DirectoryInfo(fileInfo.Name);
foreach (DirectoryInfo dir in parentDir.GetDirectories()) {   //获取文件夹
f = new FileInfoEx();
f.Text = dir.Name;
f.Name = dir.FullName;
f.FileTypeName = "文件夹"; //文件夹类型直接写OK
f.Extension = dir.Extension;
f.FileIcon = _fileIconUtil.GetDirectoryIcon(false);
files.Add(f);
}
if (isAllFiles) {
foreach (FileInfo file in parentDir.GetFiles()) {       //获取文件
f = new FileInfoEx();
f.Text = file.Name;
f.Name = file.FullName;
//***************获得文件类型-赵寒-2016-6-20**************************************
f.FileTypeName = _fileIconUtil.GetTypeName(f.Name);*********//根据文件名或扩展名得到文件类型都可
f.Extension = file.Extension;       //文件扩展名
f.IsFile = true;
f.Size = file.Length;
files.Add(f);
}
}
}
catch (UnauthorizedAccessException ce) {
_log.Exception(ce);
}
return files;
}

     做出来了，就感觉SO Easy了。开始咋没这种感觉，真是的~~~~~~哼！